I am writing a stored procedure to update multiple table's data in Postgres 9.4. I will execute this procedure from python.
CREATE OR REPLACE FUNCTION update_data(
list_table_name TEXT[],
list_parameters TEXT[]
)
RETURNS BOOLEAN LANGUAGE plpgsql SECURITY DEFINER AS $$
BEGIN
FOR i IN list_table_name LOOP
FOR j IN dict_parameters LOOP
EXECUTE '
UPDATE ' || i || '
SET default_value = ' || j.param_val || '
WHERE ' || i.id = j.id ||''
END LOOP;
END LOOP;
END;
$$
LANGUAGE 'plpgsql';
-- dict_parameters would be python list of dictionary [{"id":val,"param_val":[val1,val2,val3]},{"id":val,"param_val":[val1,val2,val3]}]
-- list_table_name would be python list containing table names.
First of all this gives me error as -
ERROR: syntax error at or near "BEGIN"
LINE 8: BEGIN
^
optimation=# END LOOP;
ERROR: syntax error at or near "LOOP"
LINE 1: END LOOP;
^
And even if it runs I am not sure if I am extracting the values the right way. If someone could guide me.
Related
I checked all related questions on SO but none helped in my case.
I have 2 loops(outside for the tables and inside for the columns). Tables are represented by 'r', and columns by 'm'. While being inside the 'm' loop which is supposed to send column values to the to-be-created trigger function. When I try to use 'NEW.m' (with trying many different formatting attempts) compiler always gives error.
Can you kindly advice on it please? Br
FOR r IN SELECT table_name FROM information_schema.tables LOOP
FOR m IN SELECT column_name FROM information_schema.columns WHERE (table_name = r.table_name ) LOOP
function_name := 'dictionary_functions_foreach_trigger';
EXECUTE format('CREATE OR REPLACE FUNCTION %s()
RETURNS trigger AS
$BODY$
DECLARE
BEGIN
IF NEW.m IS NOT NULL AND NEW.m IN (SELECT key FROM tableX.tableX_key)
THEN RETURN NEW;
END IF;
END;
$BODY$
LANGUAGE plpgsql VOLATILE
COST 100;
ALTER FUNCTION %s()
OWNER TO mydb;',function_name, function_name);
EXECUTE 'CREATE TRIGGER ' || function_name || ' BEFORE INSERT OR UPDATE ON ' || belonging_to_schema || '.' || r.table_name || ' FOR EACH ROW EXECUTE PROCEDURE ' || function_name || '();';
----Trigger Functions after edit-
EXECUTE format(
'CREATE OR REPLACE FUNCTION %s()
RETURNS trigger AS
$BODY$
DECLARE
insideIs text := %s ;
BEGIN
FOR %s IN 0..(TG_NARGS-1) LOOP
IF %I= TG_ARGV[%s]
THEN insideIs := %s ;
END IF;
END LOOP;
IF NEW.%I IS NOT NULL AND (insideIs =%s) AND NEW.%I IN (SELECT key FROM tableX.tableX_key)
THEN RETURN NEW;
ELSE RETURN OLD;
END IF;
END;
$BODY$
LANGUAGE plpgsql VOLATILE
COST 100;
ALTER FUNCTION %s()
OWNER TO mydb;' , function_name, 'notInside', 'i' , m.column_name, 'i' , 'ok', m.column_name, 'ok', m.column_name ,function_name);
You need to use another placeholder for the column name, they way you have written it, the column name "m" is hardcoded in the function.
You also don't really need the outer loop, as the table_name is also available in information_schema.columns.
Your trigger would also fail with a runtime error if the condition is not true as you don't have a return in that case. If you want to abort the statement, use return null;
You should also use format() for the create trigger statement.
FOR m IN SELECT table_schema, table_name, column_name
FROM information_schema.columns
WHERE table_name in (...)
LOOP
function_name := 'dictionary_functions_foreach_trigger';
EXECUTE format('CREATE OR REPLACE FUNCTION %I()
RETURNS trigger AS
$BODY$
DECLARE
BEGIN
IF NEW.%I IS NOT NULL AND NEW.%I IN (SELECT key FROM tableX.tableX_key) THEN
RETURN NEW;
END IF;
RETURN null; --<< you need some kind of return here!
END;
$BODY$
LANGUAGE plpgsql VOLATILE
COST 100;
ALTER FUNCTION %s()
OWNER TO mydb;', function_name, m.column_name, m.column_name, function_name, function_name);
EXECUTE format('CREATE TRIGGER %I BEFORE INSERT OR UPDATE ON %I.%I FOR EACH ROW EXECUTE PROCEDURE %I()',
function_name, m.table_schema, m.table_name, function_name);
END LOOP;
Online example
I am a newbie wrt functions and I am struggling with using the name of a table in the function body. I get an error "SQL Error [42703]: ERROR: column "tname" does not exist" when I call the function using
select "JsonToView"('data_import.import_360xero_report');
My code is below
create or replace
function data_import."JsonToView"(tname text) returns numeric
language plpgsql
as $function$
begin
do
$$
declare
l_keys text;
begin
drop view if exists v_json_view cascade;
select
string_agg(distinct format('import_data ->> %L as %I', jkey, jkey), ', ')
into
l_keys
from
import_360xero_report,
json_object_keys(import_data) as t(jkey);
execute 'create view v_json_view as select ' || l_keys || ' from ' || tname;
end;
$$;
return 0;
end $function$ ;
I have modified the code and the second create view query works with the table name but the first one does not.
Below if my modified code
create or replace
function data_import."JsonToView"(tname text) returns numeric
language plpgsql
as $function$
declare
l_keys text;
begin
drop view if exists v_json_view cascade;
execute $a$select
string_agg(distinct format('import_data ->> %L as %I', jkey, jkey), ', ')
into
l_keys
from $a$ ||
tname || $b$,
json_object_keys(import_data) as t(jkey)$b$;
execute 'create view v_json_view as select ' || l_keys || ' from ' || tname;
return 0;
end $function$ ;
The error I am getting is
SQL Error [0A000]: ERROR: EXECUTE of SELECT ... INTO is not implemented
Hint: You might want to use EXECUTE ... INTO or EXECUTE CREATE TABLE ... AS instead.
Where: PL/pgSQL function "JsonToView"(text) line 10 at EXECUTE
The problem is the superfluous nested DO statement.
The variable tname exists only in the scope of the function, not in the nested DO statement. DO is an SQL statement, not a PL/pgSQL statement, and there are no variables in SQL. Also, DO does not allow parameters.
Get rid of the DO and you will be fine.
I am new to postgres. I need to create a function that will take a list of all the tables in the database whose names are stored in one table and then delete the records of all the tables that are older than x days and have a certain row_status. Some tables do not have a row_status column.
I get an error when I try to save a written function in dbeaver -> ERROR: syntax error at or near "||"
create function delete_old_records1(day1 int, row_status1 character default null, row_status2 character default null)
returns void
language plpgsql
as $$
declare
c all_tables1%rowtype;
begin
for c in select * from all_tables1 loop
if exists(SELECT column_name FROM information_schema.columns
WHERE table_schema = 'yard_kondor' AND table_name =c.table_name AND column_name = 'row_status') then
execute 'delete from '||c.table_name||' where row_create_datetime>current_date-day1+1 and
row_status in (coalesce(row_status1,''P''), row_status2)';
else
execute 'delete from '||c.table_name||' where row_create_datetime>current_date-day1+1';
raise notice 'Table '||c.table_name||' does not have row_status column';
end if;
end loop;
return;
commit;
end;
$$
Your immediate problem is this line:
raise notice 'Table '||c.table_name||' does not have row_status column';
That should be:
raise notice 'Table % does not have row_status column', c.table_name;
However, your function could be improved a bit. In general it is highly recommended to use format() to generate dynamic SQL to properly deal with identifiers. You also can't commit in a function. If you really need that, use a procedure.
create function delete_old_records1(day1 int, row_status1 character default null, row_status2 character default null)
returns void
language plpgsql
as $$
declare
c all_tables1%rowtype;
begin
for c in select * from all_tables1
loop
if exists (SELECT column_name FROM information_schema.columns
WHERE table_schema = 'yard_kondor'
AND table_name = c.table_name
AND column_name = 'row_status') then
execute format('delete from %I
where row_create_datetime > current_date - %J + 1
and row_status in (coalesce(row_status1,%L), row_status2)', c.table_name, day1, 'P');
else
execute format('delete from %I where row_create_datetime > current_date - day1 + 1', c.table_name);
raise notice 'Table % does not have row_status column', c.table_name;
end if;
end loop;
return;
-- you can't commit in a function
end;
$$
Thank you for answer. Now I'm able to save function, but currently I have a problem with running the function.
I started the function with:
DO $$ BEGIN
PERFORM "delete_old_records1"(31,'P','N');
END $$;
I started script with ALT+X (also tried select delete_old_records1(31,'P','N');) and have this error:
SQL Error [42703]: ERROR: column "day1" does not exist
Where: PL/pgSQL function delete_old_records1(integer,character,character) line 11 at EXECUTE statement
SQL statement "SELECT "delete_old_records1"(31,'P','N')"
PL/pgSQL function inline_code_block line 2 at PERFORM
I would like to use cursor in a function with the table name as a function variable, a simple example would be a select query through cursor.
From the documentation of PostgreSQL I found that I can use
Declare curs3 CURSOR (key integer) FOR SELECT * FROM tenk1 WHERE unique1 = key;
But when I input
declare curs1 cursor (key integer) for execute 'select ' || quote_ident(colname) || ' from ' || quote_ident(tablename);
It returns ERROR: syntax error at or near "'select '".
On the other hand, if I write the function with refcursor as follows:
CREATE or replace FUNCTION cursor_hw(colname text,tablename text) RETURNS setof text AS $$
declare curs1 refcursor;
BEGIN
open curs1 for execute 'select ' || quote_ident(colname) || ' from ' || quote_ident(tablename);
for x in curs1 loop
return next x;
end loop;
END; $$ LANGUAGE plpgsql;
It will return [42601] ERROR: cursor FOR loop must use a bound cursor variable.
Any help would be appreciated, thanks a lot!
You may prefer a simple FOR record_variable IN EXECUTE <query> instead of OPEN FETCH for dynamic SQL.
CREATE or replace FUNCTION cursor_hw(colname text,tablename text)
RETURNS setof text AS
$$
DECLARE
x RECORD;
BEGIN
FOR x IN execute 'select ' || quote_ident(colname) || ' from '
|| quote_ident(tablename)
LOOP
IF x.first_name like 'D%' THEN
RETURN NEXT x;
END IF;
END LOOP;
END;
$$ LANGUAGE plpgsql;
execution
knayak=# select cursor_hw('first_name','employees');
cursor_hw
-----------
Donald
Douglas
David
Diana
Daniel
Den
David
Danielle
David
(9 rows)
I can't figure out how to access variables inside my plpgsql function. I'm using postgres 9.5 under Cygwin.
functions.sql
-- this works fine
\echo Recreate = :oktodrop
CREATE OR REPLACE FUNCTION drop_table(TEXT) RETURNS VOID AS
$$
BEGIN
IF EXISTS ( SELECT * FROM information_schema.tables WHERE table_name = $1 ) THEN
-- syntax error here:
IF (:oktodrop == 1 ) THEN
DROP TABLE $1;
END IF;
END IF;
END;
$$
language 'plpgsql';
psql.exe -v oktodrop=1 -f functions.sql
Password:
Recreate = 1
psql:functions.sql:13: ERROR: syntax error at or near ":"
LINE 5: IF (:oktodrop == 1 ) THEN
^
Perhaps I've oversimplified your task (feel free to tell me if that's the case), but why not create the function like this:
CREATE OR REPLACE FUNCTION drop_table(tablename TEXT, oktodrop integer)
RETURNS text AS
$$
DECLARE
result text;
BEGIN
IF EXISTS ( SELECT * FROM information_schema.tables WHERE table_name = tablename ) THEN
IF (oktodrop = 1 ) THEN
execute 'DROP TABLE ' || tablename;
result := 'Dropped';
ELSE
result := 'Not Okay';
END IF;
ELSE
result := 'No such table';
END IF;
return result;
END;
$$
language 'plpgsql';
Then the implementation would be:
select drop_table('foo', 1);
I should also caution that because you have not specified the table_schema field, it's conceivable that your target table exists in another schema, and the actual drop command will fail because it doesn't exist in the default schema.